Riot I believe in games that you should consider adding a game mode selection where it takes solo players who can fill much like an alternate to a tournament where it brings up games where an AFK: much like a disconnected player and replace them with a new join in playing the same champ as it was left when the AFK happened. For example if an 
quit with a
then the sub would come in with the same build and levels as well as playing the same champ.
Ok if that happens what happens if the other guy Reconnects? oh wait he can't... What if the new guy is worse? what if you lose? does the new guy get a lesser punishment since he wasn't there all game?
I think it would be better to just get a bot that does not give the enemy team more gold than a super minion if they kill it. Bots suck, yea. At least then the original person has the opportunity to connect again if they can ( Like power brown out, etc )
Or better yet, Riot, after 15 minutes of 4 v5 riot could offer a pop up to the enemy team that is up the extra player that one person leaves, they gain some LP for free to leave to balance out the game.
